[c-nsp] Replacement for HSRP

[Bob Chan]

what about IP SLA w/ reaction ?

On Dec 7, 2007 12:35 AM, Scott Granados <gsgranados at comcast.net> wrote:

> This might be like fly swatting with sledge hammers but how about BGP in
> this situation?
>
> Depending on your network addressing particulars and your ISP you could do
> something like have each router set up an IGP session between them over a
> common gig interface, then one gig out of each router to your ISP and then
> tune as needed.  If memory is a concern simply have defaults sent to you
> and
> should one link fail the route should withdraw automatically.  (as well as
> your announcement)  If you're speaking to the same ISP on both loops you
> could use a private AS.  I might be way way off here but to me this
> shouldn't require any custom scripting or hack work arounds but I may not
> be
> understanding your setup fully.
>
> Hope this helps.
>
>
> ----- Original Message -----
> From: "Bulgaria Online - Assen Totin" <assen at online.bg>
> To: <cisco-nsp at puck.nether.net>
> Sent: Thursday, December 06, 2007 8:15 AM
> Subject: [c-nsp] Replacement for HSRP
>
>
> > Hi all,
> >
> > I have a pretty weird situation and I'm trying to figure out a
> > work-around for it.
> >
> > We have 2 Cisco 2821 each equipped with a 16-port switch (Service
> > Module). Both act as gateways to a local network - each LAN device is
> > connected to both Service Modules (bonding interface) and one of the two
> > Gi ports of the each router are connected to one and same ISP.
> >
> > The Service Modules utilize HSRP to provide all LAN devices with a
> > default gateway address.
> >
> > However, the ISP blocks multicast packets on our external interfaces, so
> > the routers cannot talk to each other, hence HSRP is not actually
> > running - both external interfaces claim to be master because no slave
> > can be reached. (The ISP is in Japan and it is difficult to understand
> > why they do so; they have not been very co-operative.)
> >
> > Since the Service Modules are separate entities running their own IOS,
> > the router has no way of tracking the status of the internal interface.
> >
> > My last resort may be to connect the two routers to each other using the
> > available Gi ports on each chassis, then somehow monitor this link (if
> > one of the devices goes down, the link will go down; this is much worse
> > than HSRP, but is still better than nothing) and enable/disable the ISP
> > interface, depending on the status of this link (or may be just bring up
> > and down a secondary IP address). Basically, this means the ability to
> > enable/disable one Ethernet interface depending on the link status of
> > another Ethernet interface.
> >
> > Any ideas how to achieve this (if possible at all) are welcome - up to
> > writing a TCL job to run in the router...
> >
> > Thanks in advance,
> >
> > Assen Totin
> >
> >
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